Very cool. I made a relay logic door monitor for a very similar purpose, and I can see some definite advantages to using your more software based approach. (https://www.instructables.com/id/Bathroom-Status-Indicator-Lights-and-Automatic-Swi/) The ability to remote monitor is sweet!

The only improvement I can think of would be a setting that sends you an email or text message if either of the doors are opened. If you are going to be out of town for an extended period of time - set it - and it will contact you if someone breaks in (unless they cut your web or power prior to entry). You could also get it to send you a report at the end of day with details on the intervals the doors were open.

My grandparents had a security system installed in like the 70's that is just a big circuit and when one of the doors (including the garage doors) are open, a red light comes on to tell you that something isn't closed. If you arm the system while it's red it goes off and this big cold-war era tape reel computer thing boots up and automatically calls the police. lol. It's so cool.

Good instructable,and good intro to using a simple ethernet interface. I think I'll follow through on this for the learning experience, and because I don't want to walk downstairs after I've been in bed just to check on the garage doors that I forgot to check on earlier. I can see a similar application to let me know if the washer and/or drier are done.

What a cool idea! I've used Basic Stamps in my own projects in the past and they are a lot of fun to experiment with. In fact, I think I still have a spare BS2 sitting around my house...somewhere.
I also have a detached garage but I use a wireless camera to monitor it with via software based motion detection; primarily in case someone breaks into it. Software based motion can lead to false positives so a device like the "Garage Monitor" could be used as a more reliable means of telling the camera when to record as well as sound off a buzzer. I just might have to dust off my soldering iron :)